Holographic keyboard display

ABSTRACT

Embodiments that relate to displaying holographic keyboard and hand images in a holographic environment are provided. In one embodiment depth information of an actual position of a user&#39;s hand is received. Using the depth information, a holographic hand image representing the user&#39;s hand is displayed in a virtual hand plane in the holographic environment. In response to receiving a keyboard activation input from the user and using the depth information, the holographic keyboard image is adaptively displayed in a virtual keyboard plane in the holographic environment at a virtual distance under the holographic hand image representing the user&#39;s hand.

BACKGROUND

In some virtual reality and mixed reality display systems, it may bedesirable to enable users to provide text input using a holographickeyboard. For example, a display system may generate a keyboard hologramthat may receive input from a virtual input device controlled by a user.In some examples, the virtual input device may be a hand hologram thatmay simulate movement of a user's hand or hands to select keys on theholographic keyboard.

However, generating such a holographic keyboard-hand interface thatprovides an immersive and realistic touch-like interaction has provenchallenging. For example, while interacting with a keyboard hologram,the user may move or change positions, or the user's hand(s) may driftinadvertently. This can result in unintentional misalignment between thehand hologram and the keyboard hologram, and can interrupt and degradean otherwise immersive and realistic user interaction experience.Further, such hand drift and corresponding misalignment can cause falseselection determinations in which the system incorrectly interprets auser's hand movement as a selection of a virtual key of the keyboardhologram. Additionally, depending upon the position of the keyboardhologram relative to the user, the user may be forced to move his or herbody and/or hand(s) to an unnatural or uncomfortably fixed position toappropriately locate the hand hologram adjacent to the keyboardhologram.

SUMMARY

Various embodiments are disclosed herein that relate to displaying aholographic keyboard image and a holographic hand image representing auser's hand in a holographic environment. For example, one disclosedembodiment provides a method that includes receiving depth informationof an actual position of the user's hand. Using the depth information,the holographic hand image representing the user's hand is displayed ina virtual hand plane in the holographic environment. A keyboardactivation input is received from the user. In response to receiving thekeyboard activation input, and using the depth information of the actualposition of the user's hand, the holographic keyboard image isadaptively displayed in a virtual keyboard plane in the holographicenvironment at a virtual distance under the holographic hand imagerepresenting the user's hand.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a keyboard interface system according toan embodiment of the present disclosure.

FIG. 2 shows an example head-mounted display device according to anembodiment of the present disclosure.

FIG. 3 is a schematic view of a user interacting with a holographickeyboard image displayed via a display device according to an embodimentof the present disclosure.

FIG. 4 is a schematic side view of the user's hand of FIG. 3 and thecorresponding holographic hand image and holographic keyboard imageaccording to an embodiment of the present disclosure.

FIG. 5 is schematic side view of a user wearing a head-mounted displaydevice and interacting with a holographic hand image and a holographickeyboard image according to an embodiment of the present disclosure.

FIG. 6 is a schematic view of a holographic keyboard positioned belowtwo holographic hand images according to an embodiment of the presentdisclosure.

FIG. 7 is a schematic view of the holographic keyboard of FIG. 6 showingthe two holographic hand images at a closer virtual distance to theholographic keyboard according to an embodiment of the presentdisclosure.

FIG. 8A is a schematic end view of a holographic hand with a fingertipof an index finger located over a holographic key of a holographickeyboard image according to an embodiment of the present disclosure.

FIG. 8B a schematic partial side view of a user's index finger andfingertip that correspond to the holographic fingertip and index fingerof FIG. 8A.

FIG. 9A is a schematic end view of the holographic fingertip andholographic keyboard image of FIG. 8A showing the holographic keyextended outwardly toward the holographic fingertip according to anembodiment of the present disclosure.

FIG. 9B a schematic partial side view of the user's index finger andfingertip that correspond to the holographic fingertip and index fingerof FIG. 9A.

FIG. 10A is a schematic end view of the holographic fingertip andholographic keyboard image of FIG. 9A showing the holographic fingertipand holographic key moving toward the holographic keyboard by a virtualkey-press distance according to an embodiment of the present disclosure.

FIG. 10B is a schematic partial side view showing the user's indexfinger and fingertip corresponding to the holographic fingertip andindex finger of FIG. 10A and moving in a key-press by an actualkey-press distance according to an embodiment of the present disclosure.

FIGS. 11A, 11B and 11C are a flow chart of a method for displaying aholographic keyboard image and a holographic hand image according to anembodiment of the present disclosure.

FIG. 12 is a simplified schematic illustration of an embodiment of acomputing system.

DETAILED DESCRIPTION

FIG. 1 shows a schematic view of one embodiment of a keyboard interfacesystem 10 according to the present disclosure. The keyboard interfacesystem 10 includes a keyboard interface program 14 that may be stored inmass storage 18 of a computing device 22. The keyboard interface program14 may be loaded into memory 26 and executed by a processor 30 of thecomputing device 22 to perform one or more of the methods and processesdescribed in more detail below.

In some examples a mixed reality display program 34 may generate aholographic environment 38 that includes a holographic keyboard image42, one or two holographic hand images 46 and one or more virtualelements 50. Such holographic environment 38 may be provided to adisplay device, such as the head-mounted display (HMD) device 54 orother display device. As explained in more detail below, the HMD device54 may provide a virtual environment in the form of a mixed realityenvironment 56 that includes the holographic environment 38 and one ormore physical objects 58 in the surrounding real-world environment thatare viewable by a user 60 wearing the HMD device. Alternativelyexpressed, the mixed reality environment 56 may comprise the holographicenvironment 38 and a physical environment that are both viewable by theuser 60 via the HMD device.

In other examples, an HMD device may create a virtual environment in theform of a virtual reality experience in which only holographic and/orother virtual images are generated and displayed to a user. It will alsobe appreciated that many other types and configurations of displaydevices utilizing various display technologies and having various formfactors may also be used within the scope of the present disclosure.Such display devices may include, but are not limited to, fixed-positionmonitors, mobile devices such as smart phones, tablet computers, andnotebook computers, projection display devices, three-dimensional (3D)televisions, and other types of display devices.

The computing device 22 may take the form of a desktop computing device,a mobile computing device such as a smart phone, laptop, notebook ortablet computer, network computer, set-top box, home entertainmentcomputer, interactive television, gaming system, or other suitable typeof computing device. Additional details regarding the components andcomputing aspects of the computing device 22 are described in moredetail below with reference to FIG. 12.

The computing device 22 may be operatively connected with the HMD device54 using a wired connection, or may employ a wireless connection viaWiFi, Bluetooth, or any other suitable wireless communication protocol.As described in more detail below, the computing device 22 may alsoreceive keyboard activation input 62 from user 60 via the HMD device 54.Additionally, the example illustrated in FIG. 1 shows the computingdevice 22 as a separate component from the HMD device 54. It will beappreciated that in other examples the computing device 22 may beintegrated into the HMD device 54, or located in a common enclosure withother types of displays.

With reference now also to FIG. 2, one example of an HMD device 54 inthe form of a pair of wearable glasses 200 with a transparent display 68is provided. It will be appreciated that in other examples, the HMDdevice 54 may take other suitable forms in which a transparent,semi-transparent or non-transparent display is supported in front of aviewer's eye or eyes. It will also be appreciated that the HMD device 54shown in FIG. 1 may take the form of the HMD device 200, as described inmore detail below, or any other suitable HMD device.

With reference to FIGS. 1 and 2, in this example the HMD device 54includes a display system 64 and transparent display 68 that enablesimages to be delivered to the eyes of a user. The transparent display 68may be configured to visually augment an appearance of a physicalenvironment to a user viewing the physical environment through thetransparent display. For example, the appearance of the physicalenvironment may be augmented by graphical content (e.g., one or morepixels each having a respective color and brightness) that is presentedvia the transparent display 68 to create a mixed reality environment 56.

The transparent display 68 may also be configured to enable a user toview a physical object 58 in the physical environment through one ormore partially transparent pixels that are displaying a virtual objectrepresentation. In one example, the transparent display 68 may includeimage-producing elements located within lenses 204 (such as, forexample, a see-through Organic Light-Emitting Diode (OLED) display). Asanother example, the transparent display 68 may include a lightmodulator on an edge of the lenses 204. In this example the lenses 204may serve as a light guide for delivering light from the light modulatorto the eyes of a user. Such a light guide may enable a user to perceivea 3D holographic image located within the physical environment that theuser is viewing, while also allowing the user to view physical objectsin the physical environment.

The HMD device 54 may also include various sensors and related systems.For example, the HMD device 54 may include an eye-tracking sensor system72 that utilizes at least one inward facing sensor 208. The inwardfacing sensor 208 may be an image sensor that is configured to acquireimage data in the form of eye-tracking information from a user's eyes.Provided the user has consented to the acquisition and use of thisinformation, the eye-tracking sensor system 72 may use this informationto track a position and/or movement of the user's eyes.

In one example, the eye-tracking system 72 includes a gaze detectionsubsystem configured to detect a direction of gaze of each eye of auser. The gaze detection subsystem may be configured to determine gazedirections of each of a user's eyes in any suitable manner. For example,the gaze detection subsystem may comprise one or more light sources,such as infrared light sources, configured to cause a glint of light toreflect from the cornea of each eye of a user. One or more image sensorsmay then be configured to capture an image of the user's eyes.

Images of the glints and of the pupils as determined from image datagathered from the image sensors may be used to determine an optical axisof each eye. Using this information, the eye-tracking sensor system 72may then determine a direction and/or at what physical object or virtualobject the user is gazing. Such gaze detection data may then be providedto the keyboard interface program 14. It will be understood that thegaze detection subsystem may have any suitable number and arrangement oflight sources and image sensors.

The HMD device 54 may also include sensor systems that receive physicalenvironment data from the physical environment. For example, the HMDdevice 54 may include an optical sensor system 76 that utilizes at leastone outward facing sensor 212, such as an optical sensor. Outward facingsensor 212 may capture images and depth information from objects withinits field of view, such as gesture-based inputs or other movementsperformed by a wearer or by a person or physical object within the fieldof view.

The outward facing sensor(s) 212 may also capture 2D image informationand depth information from the physical environment and physical objectswithin the environment. In some examples, outward facing sensor 212 mayinclude a depth camera, a visible light camera such as an RGB camera, aninfrared light camera, and/or a position tracking camera. In one exampleand as described in more detail below, the outward facing sensor 212 mayinclude a field of view enabling the sensor to capture images and depthinformation from a user's hand when hanging downwardly next to theuser's leg.

In one example, one or more depth cameras may include left and rightcameras of a stereoscopic vision system. Time-resolved images from oneor more of these depth cameras may be registered to each other and/or toimages from another optical sensor such as a visible spectrum camera,and may be combined to yield depth-resolved video.

In other examples a structured light depth camera may be configured toproject a structured infrared illumination, and to image theillumination reflected from a scene onto which the illumination isprojected. A depth map of the scene may be constructed based on spacingsbetween adjacent features in the various regions of an imaged scene. Instill other examples, a depth camera may take the form of atime-of-flight depth camera configured to project a pulsed infraredillumination onto a scene and detect the illumination reflected from thescene. For example, illumination may be provided by an infrared lightsource 216. It will be appreciated that any other suitable depth cameramay be used within the scope of the present disclosure.

Outward facing sensor 212 may also capture images of physicalenvironment in which a user is situated. In one example, the mixedreality display program 34 may include a 3D modeling system that usessuch images and depth information to generate holographic environment 38that models the physical environment data that is captured.

The HMD device 54 may also include a position sensor system 80 thatutilizes one or more motion sensors 220 to enable position trackingand/or orientation sensing of the HMD device. For example, the positionsensor system 80 may be utilized to determine a head pose orientation ofa user's head. In one example, position sensor system 80 may comprise aninertial measurement unit (IMU) configured as a six-axis or six-degreeof freedom position sensor system. This example position sensor systemmay, for example, include three accelerometers and three gyroscopes toindicate or measure a change in location of the HMD device 54 withinthree-dimensional space along three orthogonal axes (e.g., x, y, z), anda change in an orientation of the HMD device about the three orthogonalaxes (e.g., roll, pitch, yaw).

In some embodiments, the outward facing sensor 212 may cooperate withthe IMU to determine the location and the orientation of the HMD device200 in six degrees of freedom. Such location and orientation informationmay be used to display, via the transparent display 68, one or morevirtual objects with a world-locked position in which a position of eachvirtual object appears to be fixed relative to real-world objectsviewable through the transparent display, and the position of eachvirtual object appears to be moveable relative to a wearer of thesee-through display.

Position sensor system 80 may also support other suitable positioningtechniques, such as GPS or other global navigation systems. Further,while specific examples of position sensor systems have been described,it will be appreciated that other suitable position sensor systems maybe used.

In some examples, motion sensors 220 may also be employed as user inputdevices, such that a user may interact with the HMD device 54 viagestures of the neck and head, or even of the body. The HMD device 54may also include a microphone system 84 that includes one or moremicrophones 224. In other examples, audio may be presented to the uservia a speaker system 88 including one or more speakers 228 on the HMDdevice 54.

The HMD device 54 may also include a processor 230 having a logicsubsystem and a storage subsystem, as discussed in more detail belowwith respect to FIG. 12, that are in communication with the varioussensors and systems of the HMD device. In one example, the storagesubsystem may include instructions that are executable by the logicsubsystem to receive signal inputs from the sensors and forward suchinputs to computing device 22 (in unprocessed or processed form), and topresent images to a user via the transparent display 68.

It will be appreciated that the HMD device 54 and related sensors andother components described above and illustrated in FIGS. 1 and 2 areprovided by way of example. These examples are not intended to belimiting in any manner, as any other suitable sensors, components,and/or combination of sensors and components may be utilized. Thereforeit is to be understood that the HMD device 54 may include additionaland/or alternative sensors, cameras, microphones, input devices, outputdevices, etc. without departing from the scope of this disclosure.Further, the physical configuration of the HMD device 54 and its varioussensors and subcomponents may take a variety of different forms withoutdeparting from the scope of this disclosure.

With reference now to FIGS. 3-7, descriptions of example use cases andembodiments of the keyboard interface system 10 and various displaydevices will now be provided. FIG. 3 is a schematic illustration of oneexample of a user 304 interacting with a holographic keyboard image 308and viewing a holographic wizard image 310 that are displayed by atelevision 312 in a room 314. In some examples the holographic keyboardimage 308 and/or holographic wizard 310 may be displayed in a world-lockdisplay mode as floating stationary in space between user 304 and thetelevision 312. In this manner, as user 304 changes his position in theroom 314, the user perceives the world-locked images as remainingstationary with respect to the television 312 and other real-worldobjects in room 314. In some examples user 304 may wear glasses (notshown) that assist in creating an augmented reality experience by, forexample, fusing two images into a single 3D holographic image that isperceived by the user to float in space.

In this example, television 312 is communicatively coupled to a set-topbox 316 that comprises a microphone 318, RGB camera 320 and depthsensing cameras 324 facing the user 304. The RGB camera 320 and depthsensing cameras 324 may have a field of view that captures the full bodyof the user 304. Set-top box 316 may also include an eye tracking system72 and a computing device 22 that includes keyboard interface program14. Using data from the depth sensing cameras 324, the set-top box 316may monitor the position of user 304 and various body parts, such as hisleft hand 330 and right hand 334. Using gaze tracking data from the eyetracking system 72, the set-top box 316 may also monitor the user's gazelocation with respect to real-world objects and holographic imagesdisplayed within the room 314.

In some examples, user 304 may desire to selectively view and interactwith the holographic keyboard image 308. For example, where user 304 isplaying an interactive game that includes holographic wizard 310, theholographic keyboard image 308 normally may not be displayed. To causethe keyboard interface program 14 to display the holographic keyboardimage 308, the user may provide keyboard activation input 62 to thekeyboard interface program 14 via the set-top box 316.

In some examples, keyboard activation input 62 may comprise audio inputprovided by user 304, such as a spoken command (“Show keyboard”, forexample). In other examples, the keyboard activation input 62 maycomprise a gesture or other triggering movement performed by the user304. For example, the keyboard activation input 62 may comprise the user304 performing a pinch gesture with one of his hands by touching the tipof his index finger to his thumb. In other examples, image data of theuser's hand may be analyzed to determine a state of tendons in the handthat corresponds to a keyboard activation input 62.

In other examples the keyboard activation input 62 may comprise the user304 nodding, rotating, tilting otherwise moving his head in apredetermined manner. It will be appreciated that a variety of differentgestures or other physical movements performed by the user 304 may beutilized as keyboard activation input 62 to trigger the display of theholographic keyboard image 308.

In some examples, the keyboard activation input 62 may comprise gazetracking data from eye-tracking system 72. For example and withreference again to FIG. 3, the keyboard interface program 14 may displaya virtual element, such as virtual text box 332, that accepts textinput. Using gaze tracking data from the eye-tracking system 72, thekeyboard interface program 14 may determine that user 304 is gazing atthe virtual text box 332. For example, the keyboard interface program 14may determine that user 304 is gazing at the virtual text box 332 for atleast a predetermined period of time, such as 1 second, 2 seconds or anysuitable period of time.

In some examples, the virtual text box 332 may be displayed in abody-lock display mode such that a location of the text box remainsfixed relative to a location of user 304. In some examples, a body-lockdisplay mode may comprise a torso-lock mode in which objects arepositioned relative to the user's torso direction. For example, atorso-locked text box 332 might float in front of the user 304, allowingthe user to tilt his head and look at the box from different angles.When the user 304 walks forward, the text box moves in the samedirection to maintain a constant distance from the user's torso, and mayalso maintain a constant angular orientation relative to the user'storso.

In some examples, the body-lock display mode may comprise a head-lockmode in which the location of the virtual text box 332 follows movementsof the user's head 350. Head-locked objects may be positioned relativeto the user's face direction, such that a floating head-locked text boxmay float in front of the user's face at the same location andorientation relative to the face, regardless of movement or rotation ofthe user's head. A head-locked text box also may be fixed in aparticular location relative to the user's view. For example, the textbox may be displayed in a lower left corner of the user's view, and maybe maintained in this corner of view regardless of the movement ororientation of the user's head 350. In this manner, the user 304 mayconveniently look around the room 314 while the virtual text box 332remains in view regardless of the orientation of the user's head 350.

In response to receiving the keyboard activation input 62, the keyboardinterface program 14 may display the holographic keyboard image 308 anda holographic hand image 340 via television 312. More particularly andwith reference also to FIG. 4, the keyboard interface program 14 mayadaptively display the holographic keyboard image 308 in a virtualkeyboard plane 400 and at a virtual distance 404 under the holographichand image 340 representing the user's right hand 334. To display theholographic hand image 340, the keyboard interface program 14 mayreceive depth information via depth sensing cameras 324 of an initialactual position 348 of the user's right hand 334. Using the depthinformation, the holographic hand image 340 may be displayed in avirtual hand plane 408.

It will be appreciated that in some examples the holographic hand image340 representing the user's right hand 334 may be generated using depthinformation and images of the user's hand to display a lifelikerepresentation of the user's actual hand. In other examples theholographic hand image 340 representing the user's right hand 334 maycomprise a generic hand image that is not based on the user's actualhand. In either example and as described in more detail below, depthinformation from depth sensing cameras 324 may be utilized to manipulatethe holographic hand image 340 to mirror the hand motions of the user'sactual hand.

As shown in FIG. 3, user 304 is standing with his hands hangingdownwardly and comfortably at his side. By contrast, the holographichand image 340 representing the user's right hand 334 is displayedgenerally upwardly with respect to user 304 and over the holographickeyboard image 308, with the back of the hand facing the user. Forpurposes of this disclosure, “generally upwardly” means a direction inwhich the knuckles of the holographic hand image 340 are above the wristas viewed by the user in the holographic environment. While the exampleof FIG. 3 shows a holographic hand image 340 representing the user'sright hand 334, it will be appreciated that in some examples aholographic hand image representing the user's left hand 330 may also bedisplayed. In other examples, a holographic hand image representing theuser's left hand 330 may be displayed alone.

Advantageously, the holographic keyboard image 308 may be adaptivelydisplayed and positioned underneath the holographic hand image 340regardless of the actual position of the user's right hand 334. In thismanner, the user 304 may immediately begin interacting with theholographic keyboard image 308 as soon as this image and the holographichand image 340 are displayed. In some examples, the keyboard interfaceprogram 14 may optimize the relative positioning of the holographic handimage 340 over the holographic keyboard image 308. For example and asshown in FIG. 3, upon initial display of the holographic hand image 340and holographic keyboard image 308, the index finger 344 of theholographic hand image may be positioned over the “J” key of theholographic keyboard image to provide a familiar starting position fortyping.

Additionally, as the keyboard interface program 14 utilizes depthinformation of the actual position(s) of the user's right hand 334and/or left hand 330, interface program 14 may enable user 304 to assumea variety of positions other than standing, while still comfortablyinteracting with the holographic keyboard image 308. In variousexamples, the user 304 may sit in a variety of positions, lay prone suchas on a couch, or assume any other comfortable bodily position in whichhis hands are within a field of view of the depth cameras 324. Asmentioned above, regardless of the actual position of the user'shand(s), the keyboard interface program 14 adaptively displays theholographic keyboard image 308 at a virtual distance 404 under theholographic hand image 340.

With reference again to the example of FIG. 3, the holographic keyboardimage 308 may be displayed such that its long side 352 extendshorizontally and substantially parallel to an X-axis of the user 304. Insome examples, the X-axis is defined as being substantially parallel toa line bisecting the user's two eyes (not shown). Additionally, thekeyboard interface program 14 may be configured to maintain the longside 352 of the holographic keyboard image 308 substantially parallel tothe X-axis of the user 304, regardless of the orientation of the user'shead 350. In this manner, the keyboard interface program 14 may furtherenable user 304 to assume a variety of positions while still comfortablyinteracting with the holographic keyboard image 308.

In some examples, the holographic hand image 340 and holographickeyboard image 308 may appear when the keyboard activation input 62 isreceived from user 304. In other examples, the holographic keyboardimage 308 may appear when the keyboard activation input 62 is received,while the holographic hand image 340 may be displayed when a hand imagetrigger is received. In some examples, the hand image trigger maycomprise the user's right hand 334 being maintained in a substantiallyconstant position for a predetermined length of time, such as 0.5seconds for example.

In other examples and depending upon an application being utilized,holographic keyboard image 308 may be continuously displayed regardlessof whether keyboard activation input 62 has been received. For example,where user 304 is utilizing a word processing application, theholographic keyboard image 308 may be continuously displayed. In theseexamples, upon receiving a keyboard activation input 62 the position ofthe holographic keyboard image 308 may be adjusted to the virtualkeyboard plane 400 that is at the virtual distance 404 from theholographic hand image 340.

With reference now to FIG. 4, in some examples the keyboard interfaceprogram 14 may determine that the user's hand 334 in the initial actualposition 348 is spaced by an initial actual distance 420 from theset-top box 316 comprising the depth cameras 324 that provide depthinformation. As shown in FIG. 4, with the user's hand 334 in the initialactual position 348, the holographic hand image 340 is displayed at thevirtual distance 404 under the holographic hand image. The keyboardinterface program 14 then may determine that the user's hand 334 movesto an updated actual position 428 that is an updated actual distance 432from the set-top box 316. In this example, the updated actual distance432 is less than the initial actual distance 420. In other examples, theupdated actual distance 432 may be greater than the initial actualdistance 420.

In response to determining that the user's hand 334 moves to the updatedactual distance 432 from the set-top box 316, the keyboard interfaceprogram 14 may be configured to maintain the holographic keyboard image308 at substantially the virtual distance 404 under the holographic handimage 340 representing the user's hand. In this manner, the keyboardinterface program 14 advantageously provides a consistent userinteraction experience by allowing the user's hand 334 to drift or movewhile maintaining the holographic keyboard image 308 at a substantiallyconstant distance under the holographic hand image 340. Also and asnoted above, this further enables the user 304 to change the locationand/or orientation of his body and/or hands while maintaining theholographic keyboard image 308 at a consistent distance under theholographic hand image 340.

As schematically illustrated in the example of FIG. 4, the virtual handplane 408 of the holographic hand image 340 may form an interactionangle 440 with the virtual keyboard plane 400 of the holographickeyboard image 308. In various examples, the interaction angle 440 maybe 0 degrees, 5 degrees, 10 degrees, or any other suitable angle. As theuser's hand 334 changes position, the keyboard interface program 14 maydetermine that an initial actual plane 444 of the user's hand changes bya rotation angle 450 to an updated actual plane 454.

Advantageously, and in response to determining that the initial actualplane 444 changes by the rotation angle 450 to the updated actual plane454, the keyboard interface program 14 may substantially maintain theinteraction angle 440 between the virtual hand plane 408 of theholographic hand image 340 and the virtual keyboard plane 400 of theholographic keyboard image 308. In this manner, the keyboard interfaceprogram 14 further facilitates a consistent user interaction experienceby allowing the user's hand 334 to drift or move while maintaining asubstantially constant interaction angle 440 between the virtual handplane 408 and the virtual keyboard plane 400 of the holographic keyboardimage 308.

With reference now to FIG. 5, a schematic side view of a user 504wearing an HMD device 508 and interacting with a holographic hand image512 and a holographic keyboard image 516 is provided. A display system64 of the HMD device 508 may have a display field of view 520 in whichthe holographic hand image 512, holographic keyboard image 516 and otherimages may be displayed to the user 504. The HMD device 508 may alsohave an optical sensor system 76 including one or more depth sensorshaving a capture field of view 530 within which the sensors may capturedepth information.

As shown in FIG. 5, with the user 504 allowing his hand 540 to restcomfortably by his side, the user's hand is located outside of thedisplay field of view 520 of the HMD device 508 but within the capturefield of view 530 of the depth sensors of the HMD device.Advantageously, in this manner the keyboard interface program 14 enablesthe user 504 to stand in a relaxed position with his hands by his sideand interact with the holographic keyboard image 516 via holographichand image 512 as described above.

In some examples, the keyboard interface program 14 may be configured todisplay one or more virtual shadows on a holographic keyboard imagebelow one or more holographic hand images to provide a visual locationcue of the virtual distance between the holographic hand image and theholographic keyboard image. For example and with reference now to FIGS.6 and 7, in one example a holographic left hand image 602 may bedisplayed over a holographic keyboard image 606 and positioned such thata fingertip 610 of the index finger 614 of the hand image is locatedover a holographic control key 618 of the keyboard image. As describedabove, the holographic left hand image 602, index finger 614 andfingertip 610 correspond to an orientation of the physical left hand,index finger and fingertip of a user, such as user 304.

To provide the user with a visual location cue of the virtual distancebetween the holographic left hand image 602 and the holographic keyboardimage 606, the keyboard interface program 14 may display a left handvirtual shadow 630 on the holographic keyboard image and underneath theleft hand image. With reference now to FIG. 7, as the user moves herphysical left hand to cause the holographic fingertip 610 to advancetoward the holographic control key 618, the left hand virtual shadow 630may be correspondingly moved under the holographic left hand image 602to visually converge with the left hand image. In this manner, the userreceives a visual location cue that the holographic fingertip 610 isadvancing towards the holographic control key 618.

In another example and as shown in FIG. 6, a first right hand shadow 640and second right hand shadow 644 may be utilized to provide a visuallocation cue of the virtual distance between a holographic right handimage 650 and the holographic keyboard image 606. In this example, theholographic right hand image 650 is displayed over the holographickeyboard image 606 and positioned such that a fingertip 654 of indexfinger 658 is located over a holographic arrow key 662 of the keyboardimage. As described above, the holographic right hand image 650, indexfinger 658 and fingertip 654 correspond to an orientation of thephysical right hand, index finger and fingertip of a user, such as user304.

In this example and with reference now to FIG. 7, the user may move herphysical right hand to cause the holographic fingertip 654 to advancetoward the holographic arrow key 662. Corresponding to this movement,the first right hand shadow 640 and second right hand shadow 644 may bemoved towards one another under the holographic right hand image 650 tovisually converge at the holographic arrow key 662. In this manner, theuser receives a visual location cue that the holographic fingertip 654is advancing towards the holographic arrow key 662.

In other examples and with reference again to FIG. 6, the keyboardinterface program 14 may determine that holographic fingertip 610 of theholographic left hand image 602 is located over the holographic controlkey 618. In response, the holographic interface program 14 may broadcastone or more audio location cues that indicate to a user that aholographic fingertip is located over a holographic key of theholographic keyboard image 606. In this manner, the user may be assistedin manipulating a holographic fingertip to select a desired holographickey.

With reference now to FIG. 8A and in other examples, the keyboardinterface program 14 may animate one or more holographic keys of aholographic keyboard to facilitate a user's interaction with thekeyboard via a holographic hand image. As schematically shown in FIG.8A, the keyboard interface program 14 may display a holographic righthand image 802 that corresponds to a user's physical right hand asdiscussed above. In this example and to match an orientation of theuser's physical right hand, the holographic right hand image 802 forms apointing gesture in which the holographic index finger 806 is extended.As shown in FIG. 8A, the index fingertip 810 is located over a selectedholographic key 814 of a holographic keyboard image 818. FIG. 8Bschematically illustrates the actual index finger 822 and actual indexfingertip 826 of the user's physical right hand which are modeled by theholographic index finger 806 and index fingertip 810 of FIG. 8A.

In some examples, the keyboard interface program 14 may determine thatthe holographic index fingertip 810 of the holographic hand image 802 islocated over the selected holographic key 814 of the holographickeyboard image 818. With reference now to FIG. 9A, and in response todetermining that the holographic index fingertip 810 is located over theselected holographic key 814, the keyboard interface program 14 mayanimate the holographic key to extend outwardly toward the holographicfingertip and to an extended position 820. In some examples theholographic key 814 may be extended to touch the holographic fingertip810. Advantageously, in this manner the user may visually perceive theholographic key 814 touching the holographic fingertip 810 of theextended holographic index finger 806. In other examples, theholographic key 814 may be moved outwardly toward the holographicfingertip 810 but may not touch the holographic fingertip. As shown inFIG. 9B, during this animation the user's actual index finger 822 mayremain substantially stationary.

With reference now to FIG. 10B, the user may desire to select theselected holographic key 814. Accordingly, the user may move thephysical fingertip 826 of his index finger 822 in a key-press direction,as indicated by action arrow K, by an actual key-press distance 830.Correspondingly, and in response to determining that the physicalfingertip 826 moves in key-press direction K by actual key-pressdistance 830, the keyboard interface program 14 may animate theholographic fingertip 810 and the holographic key 814 to move toward theholographic keyboard image 818 by a virtual key-press distance 840 thatis less than the actual key-press distance 830.

Advantageously, by selectively moving the holographic fingertip 810 andholographic key 814 by a virtual key-press distance 840 that is lessthan the actual key-press distance 830, the keyboard interface program14 may visually simulate haptic friction between the holographic key andthe holographic keyboard. Alternatively expressed, by truncating thevisual movement of the holographic fingertip 810 and holographic key 814as compared to the actual movement of the user's fingertip 826, thekeyboard interface program 14 visually simulates the holographic key 814contacting an obstacle within the holographic keyboard image 818 thatstops movement of the key. In some examples, once movement of theholographic key 814 has ceased, the holographic index finger 806 may beanimated to continue rotating around the point of contact between thefingertip 810 and the key. Advantageously, such visual simulations mayprovide the user with a perception of the selection of the key in amanner similar to the tactile interaction provided by the keys of aphysical keyboard.

FIGS. 11A, 11B, and 11C illustrate a flow chart of a method 1100 formethod for displaying a holographic keyboard image and a holographichand image representing a user's hand in a holographic environmentaccording to an embodiment of the present disclosure. The followingdescription of method 1100 is provided with reference to the softwareand hardware components of the keyboard interface system 10 describedabove and shown in FIGS. 1-10. It will be appreciated that method 1100may also be performed in other contexts using other suitable hardwareand software components.

With reference now to FIG. 11A, at 1104 the method 100 may includereceiving depth information of an actual position of a user's hand. At1108 the method 1100 may include, using the depth information,displaying the holographic hand image representing the user's hand in avirtual hand plane in the holographic environment. At 1112 the method1100 may include receiving a keyboard activation input from the user. At1116 the method 1100 may include displaying a virtual element thataccepts text input. At 1120 the method 1100 may include receiving akeyboard activation input by determining that the user is gazing at thevirtual element. At 1124 the keyboard activation input may compriseaudio input from the user.

At 1128, in response to receiving the keyboard activation input andusing the depth information of the actual position of the user's hand,the method 1100 may include adaptively displaying the holographickeyboard image in a virtual keyboard plane in the holographicenvironment at a virtual distance under the holographic hand imagerepresenting the user's hand. At 1132 the method 1100 may includedetermining that the user's hand is spaced by an initial actual distancefrom a capture device that provides the depth information. At 1136 themethod 1100 may include determining that the user's hand moves to anupdated actual distance from the capture device. At 1140 the method 1100may include, in response to determining that the user's hand moves tothe updated actual distance from the capture device, maintaining theholographic keyboard image at substantially the virtual distance underthe holographic hand image representing the user's hand.

With reference now to FIG. 11B, at 1144 the virtual hand plane of theholographic hand image may form an interaction angle with the virtualkeyboard plane of the holographic keyboard image. At 1148 the method1100 may include determining that an initial actual plane of the user'shand changes by a rotation angle to an updated actual plane. At 1152, inresponse to determining that the initial actual plane changes by therotation angle to the updated actual plane, the method 1100 may includesubstantially maintaining the interaction angle between the virtual handplane of the holographic hand image and the virtual keyboard plane ofthe holographic keyboard image.

At 1156 the actual position of the user's hand may be outside a displayfield of view of a display system that displays the holographic keyboardimage and the holographic hand image, and the actual position of theuser's hand may be within a capture field of view of a capture devicethat provides the depth information. At 1158 the method 1100 may includedisplaying one or more virtual shadows on the holographic keyboard imagebelow the holographic hand image to provide a visual location cue of thevirtual distance between the holographic hand image and the holographickeyboard image.

At 1162 the method 1100 may include determining that a holographicfingertip of the holographic hand image is located over a holographickey of the holographic keyboard image. At 1166, in response todetermining that the holographic fingertip is located over theholographic key, the method 1100 may include broadcasting one or moreaudio location cues to the user. At 1170, in response to determiningthat the holographic fingertip is located over the holographic key, themethod 1100 may include animating the holographic key to extendoutwardly toward the holographic fingertip.

With reference now to FIG. 11C, where a holographic fingertip of theholographic hand image corresponds to a physical fingertip of the user'shand, at 1174 the method 1100 may include determining that the physicalfingertip of the user's hand moves in a key-press direction by an actualkey-press distance. At 1178, in response to determining that thephysical fingertip moves in the key-press direction, the method 1100 mayinclude animating the holographic fingertip and the holographic key tomove toward the holographic keyboard by a virtual key-press distancethat is less than the actual key-press distance to simulate frictionbetween the holographic key and the holographic keyboard.

It will be appreciated that method 1100 is provided by way of exampleand is not meant to be limiting. Therefore, it is to be understood thatmethod 1100 may include additional and/or alternative steps than thoseillustrated in FIGS. 11A, 11B and 11C. Further, it is to be understoodthat method 1100 may be performed in any suitable order. Further still,it is to be understood that one or more steps may be omitted from method1100 without departing from the scope of this disclosure.

FIG. 12 schematically shows a nonlimiting embodiment of a computingsystem 1200 that may perform one or more of the above described methodsand processes. Computing device 22 may take the form of computing system1200. Computing system 1200 is shown in simplified form. It is to beunderstood that virtually any computer architecture may be used withoutdeparting from the scope of this disclosure. In different embodiments,computing system 1200 may take the form of a mainframe computer, servercomputer, desktop computer, laptop computer, tablet computer, homeentertainment computer, network computing device, mobile computingdevice, mobile communication device, gaming device, etc. As noted above,in some examples the computing system 1200 may be integrated into an HMDdevice.

As shown in FIG. 12, computing system 1200 includes a logic subsystem1204 and a storage subsystem 1208. Computing system 1200 may optionallyinclude a display subsystem 1212, a communication subsystem 1216, asensor subsystem 1220, an input subsystem 1222 and/or other subsystemsand components not shown in FIG. 12. Computing system 1200 may alsoinclude computer readable media, with the computer readable mediaincluding computer readable storage media and computer readablecommunication media. Computing system 1200 may also optionally includeother user input devices such as keyboards, mice, game controllers,and/or touch screens, for example. Further, in some embodiments themethods and processes described herein may be implemented as a computerapplication, computer service, computer API, computer library, and/orother computer program product in a computing system that includes oneor more computers.

Logic subsystem 1204 may include one or more physical devices configuredto execute one or more instructions. For example, the logic subsystem1204 may be configured to execute one or more instructions that are partof one or more applications, services, programs, routines, libraries,objects, components, data structures, or other logical constructs. Suchinstructions may be implemented to perform a task, implement a datatype, transform the state of one or more devices, or otherwise arrive ata desired result.

The logic subsystem 1204 may include one or more processors that areconfigured to execute software instructions. Additionally oralternatively, the logic subsystem may include one or more hardware orfirmware logic machines configured to execute hardware or firmwareinstructions. Processors of the logic subsystem may be single core ormulticore, and the programs executed thereon may be configured forparallel or distributed processing. The logic subsystem may optionallyinclude individual components that are distributed throughout two ormore devices, which may be remotely located and/or configured forcoordinated processing. One or more aspects of the logic subsystem maybe virtualized and executed by remotely accessible networked computingdevices configured in a cloud computing configuration.

Storage subsystem 1208 may include one or more physical, persistentdevices configured to hold data and/or instructions executable by thelogic subsystem 1204 to implement the herein described methods andprocesses. When such methods and processes are implemented, the state ofstorage subsystem 1208 may be transformed (e.g., to hold differentdata).

Storage subsystem 1208 may include removable media and/or built-indevices. Storage subsystem 1208 may include optical memory devices(e.g., CD, DVD, HD-DVD, Blu-Ray Disc, etc.), semiconductor memorydevices (e.g., RAM, EPROM, EEPROM, etc.) and/or magnetic memory devices(e.g., hard disk drive, floppy disk drive, tape drive, MRAM, etc.),among others. Storage subsystem 1208 may include devices with one ormore of the following characteristics: volatile, nonvolatile, dynamic,static, read/write, read-only, random access, sequential access,location addressable, file addressable, and content addressable.

In some embodiments, aspects of logic subsystem 1204 and storagesubsystem 1208 may be integrated into one or more common devices throughwhich the functionally described herein may be enacted, at least inpart. Such hardware-logic components may include field-programmable gatearrays (FPGAs), program- and application-specific integrated circuits(PASIC/ASICs), program- and application-specific standard products(PSSP/ASSPs), system-on-a-chip (SOC) systems, and complex programmablelogic devices (CPLDs), for example.

FIG. 12 also shows an aspect of the storage subsystem 1208 in the formof removable computer readable storage media 1224, which may be used tostore data and/or instructions executable to implement the methods andprocesses described herein. Removable computer-readable storage media1224 may take the form of CDs, DVDs, HD-DVDs, Blu-Ray Discs, EEPROMs,and/or floppy disks, among others.

It is to be appreciated that storage subsystem 1208 includes one or morephysical, persistent devices. In contrast, in some embodiments aspectsof the instructions described herein may be propagated in a transitoryfashion by a pure signal (e.g., an electromagnetic signal, an opticalsignal, etc.) that is not held by a physical device for at least afinite duration. Furthermore, data and/or other forms of informationpertaining to the present disclosure may be propagated by a pure signalvia computer-readable communication media.

When included, display subsystem 1212 may be used to present a visualrepresentation of data held by storage subsystem 1208. As the abovedescribed methods and processes change the data held by the storagesubsystem 1208, and thus transform the state of the storage subsystem,the state of the display subsystem 1212 may likewise be transformed tovisually represent changes in the underlying data. The display subsystem1212 may include one or more display devices utilizing virtually anytype of technology. Such display devices may be combined with logicsubsystem 1204 and/or storage subsystem 1208 in a shared enclosure, orsuch display devices may be peripheral display devices. The displaysubsystem 1212 may include, for example, the display system 64 andtransparent display 68 of the HMD device 54.

When included, communication subsystem 1216 may be configured tocommunicatively couple computing system 1200 with one or more networksand/or one or more other computing devices. Communication subsystem 1216may include wired and/or wireless communication devices compatible withone or more different communication protocols. As nonlimiting examples,the communication subsystem 1216 may be configured for communication viaa wireless telephone network, a wireless local area network, a wiredlocal area network, a wireless wide area network, a wired wide areanetwork, etc. In some embodiments, the communication subsystem may allowcomputing system 1200 to send and/or receive messages to and/or fromother devices via a network such as the Internet.

When included, sensor subsystem 1220 may include one or more sensorsconfigured to sense different physical phenomenon (e.g., visible light,infrared light, sound, acceleration, orientation, position, etc.) asdescribed above. Sensor subsystem 1220 may be configured to providesensor data to logic subsystem 1204, for example. As described above,such data may include depth information, eye-tracking information, imageinformation, audio information, ambient lighting information, positioninformation, motion information, user location information, and/or anyother suitable sensor data that may be used to perform the methods andprocesses described above.

When included, input subsystem 1222 may comprise or interface with oneor more sensors or user-input devices such as a game controller, gestureinput detection device, voice recognizer, inertial measurement unit,keyboard, mouse, or touch screen. In some embodiments, the inputsubsystem 1222 may comprise or interface with selected natural userinput (NUI) componentry. Such componentry may be integrated orperipheral, and the transduction and/or processing of input actions maybe handled on- or off-board. Example NUI componentry may include amicrophone for speech and/or voice recognition; an infrared, color,stereoscopic, and/or depth camera for machine vision and/or gesturerecognition; a head tracker, eye tracker, accelerometer, and/orgyroscope for motion detection and/or intent recognition; as well aselectric-field sensing componentry for assessing brain activity.

The term “program” may be used to describe an aspect of the keyboardinterface system 10 that is implemented to perform one or moreparticular functions. In some cases, such a program may be instantiatedvia logic subsystem 1204 executing instructions held by storagesubsystem 1208. It is to be understood that different programs may beinstantiated from the same application, service, code block, object,library, routine, API, function, etc. Likewise, the same program may beinstantiated by different applications, services, code blocks, objects,routines, APIs, functions, etc. The term “program” is meant to encompassindividual or groups of executable files, data files, libraries,drivers, scripts, database records, etc.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. As such, various acts illustrated may beperformed in the sequence illustrated, in other sequences, in parallel,or in some cases omitted. Likewise, the order of the above-describedprocesses may be changed.

The subject matter of the present disclosure includes all novel andnonobvious combinations and subcombinations of the various processes,systems and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

1. A method for displaying a holographic keyboard image and aholographic hand image representing a user's hand in a holographicenvironment, the method comprising: receiving depth information of anactual position of the user's hand; using the depth information,displaying the holographic hand image representing the user's hand in avirtual hand plane in the holographic environment; receiving a keyboardactivation input from the user; and in response to receiving thekeyboard activation input, and using the depth information of the actualposition of the user's hand, adaptively displaying the holographickeyboard image in a virtual keyboard plane in the holographicenvironment at a virtual distance under the holographic hand imagerepresenting the user's hand.
 2. The method of claim 1, furthercomprising: determining that the user's hand is spaced by an initialactual distance from a capture device that provides the depthinformation; determining that the user's hand moves to an updated actualdistance from the capture device; and in response to determining thatthe user's hand moves to the updated actual distance from the capturedevice, maintaining the holographic keyboard image at substantially thevirtual distance under the holographic hand image representing theuser's hand.
 3. The method of claim 1, wherein the virtual hand plane ofthe holographic hand image forms an interaction angle with the virtualkeyboard plane of the holographic keyboard image, the method furthercomprising: determining that an initial actual plane of the user's handchanges by a rotation angle to an updated actual plane; and in responseto determining that the initial actual plane changes by the rotationangle to the updated actual plane, substantially maintaining theinteraction angle between the virtual hand plane of the holographic handimage and the virtual keyboard plane of the holographic keyboard image.4. The method of claim 1, further comprising: displaying a virtualelement that accepts text input; and wherein receiving the keyboardactivation input further comprises determining that the user is gazingat the virtual element.
 5. The method of claim 1, wherein the keyboardactivation input comprises audio input from the user.
 6. The method ofclaim 1, wherein the actual position of the user's hand is outside adisplay field of view of a display system that displays the holographickeyboard image and the holographic hand image, and the actual positionof the user's hand is within a capture field of view of a capture devicethat provides the depth information.
 7. The method of claim 1, furthercomprising: displaying one or more virtual shadows on the holographickeyboard image below the holographic hand image to provide a visuallocation cue of the virtual distance between the holographic hand imageand the holographic keyboard image.
 8. The method of claim 1, furthercomprising: determining that a holographic fingertip of the holographichand image is located over a holographic key of the holographic keyboardimage; and in response to determining that the holographic fingertip islocated over the holographic key, animating the holographic key toextend outwardly toward the holographic fingertip.
 9. The method ofclaim 1, wherein a holographic fingertip of the holographic hand imagecorresponds to a physical fingertip of the user's hand, the methodfurther comprising: determining that the holographic fingertip islocated over a holographic key of the holographic keyboard image;determining that the physical fingertip of the user's hand moves in akey-press direction by an actual key-press distance; in response todetermining that the physical fingertip moves in the key-pressdirection, animating the holographic fingertip and the holographic keyto move toward the holographic keyboard by a virtual key-press distancethat is less than the actual key-press distance to simulate frictionbetween the holographic key and the holographic keyboard.
 10. The methodof claim 1, further comprising: determining that a holographic fingertipof the holographic hand image is located over a holographic key of theholographic keyboard image; and in response to determining that theholographic fingertip of the holographic hand image is located over theholographic key of the holographic keyboard image, broadcasting one ormore audio location cues.
 11. A keyboard interface system for displayinga holographic keyboard image and a holographic hand image representing auser's hand in a holographic environment, the keyboard interface systemcomprising: a display system; a keyboard interface program executed by aprocessor of a computing device, the keyboard interface programconfigured to: receive depth information of an actual position of theuser's hand; using the depth information, display via the display systemthe holographic hand image representing the user's hand in a virtualhand plane in the holographic environment; receive a keyboard activationinput from the user; and in response to receiving the keyboardactivation input, and using the depth information of the actual positionof the user's hand, adaptively display via the display system theholographic keyboard image in a virtual keyboard plane in theholographic environment at a virtual distance under the holographic handimage representing the user's hand.
 12. The keyboard interface system ofclaim 11, wherein the keyboard interface program is further configuredto: determine that the user's hand is spaced by an initial actualdistance from a capture device that provides the depth information;determine that the user's hand moves to an updated actual distance fromthe capture device; and in response to determining that the user's handmoves to the updated actual distance from the capture device, maintainthe holographic keyboard image at substantially the virtual distanceunder the holographic hand image representing the user's hand.
 13. Thekeyboard interface system of claim 11, wherein the virtual hand plane ofthe holographic hand image forms an interaction angle with the virtualkeyboard plane of the holographic keyboard image, and the keyboardinterface program is further configured to: determine that an initialactual plane of the user's hand changes by a rotation angle to anupdated actual plane; and in response to determining that the initialactual plane changes by the rotation angle to the updated actual plane,substantially maintain the interaction angle between the virtual handplane of the holographic hand image and the virtual keyboard plane ofthe holographic keyboard image.
 14. The keyboard interface system ofclaim 11, wherein the keyboard interface program is further configuredto: display a virtual element that accepts text input; and whereinreceiving the keyboard activation input further comprises determiningthat the user is gazing at the virtual element.
 15. The keyboardinterface system of claim 11, further comprising a capture device thatcaptures the depth information, and wherein the actual position of theuser's hand is outside a display field of view of the display system,and the actual position of the user's hand is within a capture field ofview of the capture device.
 16. The keyboard interface system of claim15, wherein the display system, the computing device, and the capturedevice are located on a head-mounted display device.
 17. The keyboardinterface system of claim 11, wherein the keyboard interface program isfurther configured to: determine that a holographic fingertip of theholographic hand image is located over a holographic key of theholographic keyboard image; and in response to determining that theholographic fingertip is located over the holographic key, animate theholographic key to extend outwardly toward the holographic fingertip.18. The keyboard interface system of claim 11, wherein a holographicfingertip of the holographic hand image corresponds to a physicalfingertip of the user's hand, and the keyboard interface program isfurther configured to: determine that the holographic fingertip islocated over a holographic key of the holographic keyboard image;determine that the physical fingertip of the user's hand moves in akey-press direction by an actual key-press distance; and in response todetermining that the physical fingertip moves in the key-pressdirection, animate the holographic fingertip and the holographic key tomove toward the holographic keyboard by a virtual key-press distancethat is less than the actual key-press distance to simulate frictionbetween the holographic key and the holographic keyboard.
 19. Thekeyboard interface system of claim 11, wherein the keyboard interfaceprogram is further configured to: determine that a holographic fingertipof the holographic hand image is located over a holographic key of theholographic keyboard image; and in response to determining that aholographic fingertip of the holographic hand image is located over aholographic key of the holographic keyboard image, broadcast one or moreaudio location cues.
 20. A head-mounted display device, comprising: adisplay system; a computing device; and a keyboard interface programexecuted by a processor of the computing device, the keyboard interfaceprogram configured to: receive depth information of an actual positionof the user's hand; using the depth information, display via the displaysystem the holographic hand image representing the user's hand in avirtual hand plane in the holographic environment; receive a keyboardactivation input from the user; in response to receiving the keyboardactivation input, and using the depth information of the actual positionof the user's hand, adaptively display via the display system theholographic keyboard image in a virtual keyboard plane in theholographic environment at a virtual distance under the holographic handimage representing the user's hand, wherein the virtual hand plane ofthe holographic hand image forms an interaction angle with the virtualkeyboard plane of the holographic keyboard image; determine that aninitial actual plane of the user's hand changes by a rotation angle toan updated actual plane; and in response to determining that the initialactual plane changes by the rotation angle to the updated actual plane,substantially maintain the interaction angle between the virtual handplane of the holographic hand image and the virtual keyboard plane ofthe holographic keyboard image.